1. Field of the Invention
The present invention relates to a pressure alarm device. More specifically, the present invention relates to a pressure alarm device operable with, or incorporated into, a pressure gauge incorporated into a pressure regulator for a gas cylinder.
2. Description of the Related Art
Balloons and inflatable advertising displays are often filled with conventional gas cylinder units. Most frequently, this type of conventional gas cylinder unit includes a gas cylinder containing Helium (He), but other conventional non-combustible gasses (Nitrogen and Argon) are also used.
In some circumstances, conventional gas cylinder units also include a control mechanism, frequently placed on the top of the gas cylinder for user convenience. Conventional gas cylinder control mechanisms are threaded into the top of the gas cylinder and are often actuated by a control valve of conventional design. Conventional control mechanisms include a pressure control valve (usually a ball or a needle valve), a combination pressure regulator and gauge, and at least one male filling adapter that mates with a balloon or display opening during filling to provide a gas tight seal. Frequently, multiple male extensions are used to allow ready adaptation with a variety of balloon types.
Conventionally combined pressure regulator and gauge sets include a conventional regulator with a visual gauge and a safety pressure relief device or over-pressure vent opening. Conventional visual gauges have a body enclosing a face and an indicator needle. The needle is registered against a scale printed on the face of the gauge. The needle is most frequently connected to a conventional Bourdon-tube type gauge movement and directly reflects an existing gas cylinder pressure when the conventional regulator is open. Using this type of combined regulator/gauge set, operators may both regulate the available pressure (by opening and closing the regulator) and monitor the existing gas cylinder pressure by viewing the visual gauge.
In an alternative conventional circumstance, a pressure regulator gauge is connected to a propane (LP) cylinder of the type normally associated with a back-yard gas grill. A control valve, in a direct line with the gauge, opens the LP cylinder providing propane access to the grill via a braided hose and a set of quick-disconnect fittings. In use, an operator connects the braided hose to a coupling down stream from the pressure regulator gauge. As the operator opens the valve, the gauge reads the tank pressure. As the LP gas is used, the gauge generally reflects the remaining pressure in the tank and hence the remaining volume of LP gas.
In either conventional circumstance, certain design and safety standards may govern the type of connections and fittings which are used. Particularly of note are the design and safety standards governing conventional pressure regulator gauges are prepared by the Compressed Gas Association (CGA) and other governmental bodies to protect the public.
Unfortunately, end users for either type of conventional gas cylinder unit (LP, He, N, etc.) are often untrained and unsophisticated in monitoring the visual gauges and scheduling appropriate replacement gas cylinder delivery. Additionally, the balloon/entertainment and advertisement industries often cannot afford to competently train end users and may experience sudden workflow changes making reliable and regular cylinder replacement scheduling difficult. Over ordering of replacement gas cylinders increases inventory costs. Under ordering of replacement gas cylinder results in sudden operational shut down and client loss. Finally, conventional indicator needle-type combination pressure regulator gauges often include small and inaccurate scales and are often difficult to read from any distance.
Attempts to make conventional visual gauges more useful include labeling the gauge face, adjacent a zero (0) pressure value, a warning color or other indicia of low pressure. One conventional gauge-less regulator (without a needle-type gauge) includes a spring-loaded “pop-up” indicator providing a visual indicator of low pressure. Unfortunately, these conventional low-pressure warning systems are small, are hard to read, are easily hidden by dirt, or require experience or training to read. Unfortunately, there is no conventionally available and adaptable alarm system for conventional types of gas cylinder units that would overcome these problems and provide easy end user with a simple and cheap warning prior to emptying the gas cylinder.
While complex conventional pressure sensing and alarm system exist, these systems require custom design and are often regulated by external and large computerized feed-back and pressure-check loops, the high cost and maintenance fees associated with acquisition and operation of these systems is prohibitive to the home grilling, balloon, and advertising display industry. Additionally, these large conventional pressure sensing and alarm systems often require lengthy hard-wire connections with separate computer modules and a full time power supply to function reliably.
In summary, the problems of commercially available combination pressure regulator gauges include:                1. Lack of positive audible, visible, or vibratory alarm signal to warn unskilled end users of low-pressure level.        2. High purchase, installation, and maintenance costs for conventionally available systems.        3. Poor gauge face resolution making accurate gauge reading difficult by unsophisticated end users.        4. Lack of adaptable pressure alarms that can be applied to existing conventional pressure regulator gauges in the field without complex or hard-wire support systems for power supplies and sensor operation.        5. Low portability and difficulty in repositioning on replacement modules.        6. Lack of easy communication and/or control between a gauge and an off-site monitor, controller, owner.        